TiO2 Nanotube Layers on Ti Substrates for High Efficiency Flexible Dye-Sensitized Solar Cells

We report herein the promising application of TiO2 nanotubes formed on a Ti substrate to a flexible dye-sensitized solar cell illuminated from the back-side. We found that anodization of a Ti substrate in an extremely dilute perchloric acid solution yielded the formation of a high aspect-ratio TiO2 nanotube layer on the Ti substrate. The nanotube layer has the equivalent surface area for dye-adsorption to a TiO2 nanoparticle layer. This novel one-dimensional TiO2 material provided efficient carrier generation interfaces as well as an efficient transport pathway for the carriers, evidenced by the enhanced photocurrent and photovoltage of the cell. (C) 2008 The Japan Society of Applied Physics